Fasting (8 hours) required. For 12 hours before specimen collection, do not take multivitamins or dietary supplements containing biotin (vitamin B7), which is commonly found in hair, skin, and nail supplements and multivitamins.
If medically feasible, proton pump inhibitor (omeprazole, lansoprazole, dexlansoprazole, esomeprazole, pantoprazole, and rabeprazole) therapy should be discontinued 1 week before measurement of serum gastrin levels.
Drugs that interfere with gastrointestinal motility (eg. opioids) should be discontinued for at least 2 weeks before serum gastrin testing.
If multiple specimens are collected, submit each gold top tube under a separate order. Specimen should be labelled with corresponding collection time.

1. Draw sufficient blood into gold top tube.
2. Gently invert the tube 5 times.
3. Send specimen to the laboratory immediately.

Refer to testing laboratory test catalogue for more information:
https://www.mayocliniclabs.com/test-catalog/overview/8512